Extension bit



\E. FREY 2,226,762

EXTENSION BIT 2 Sheets-Sheet 1 Filed April 21, 1939 Dec. 31', 1940. E. FREY 2,226,762

EXTENSION am Filed April 21. 1959 2 Sheet-Sheet 2 Inventor iqn 1;. I Y

A iiorneys Patented Dec. 31, 1940 UNITED STATES PTENT OFFICE EXTENSION BIT Edward Frey,

Modesto, Calif.

Application April 21, 1939, Serial No. 269,263

1 Claim.

This invention relates to extension bits wherein a bit operates in conjunction with a drill or other suitable center; and an object of the invention is to provide an extension bit of this character having certain new and useful improvements over such extension bits as are now known and in use, and which will, in general, be stronger, more durable, and adjustable to greater accuracy than the present-day bit.

The invention together with its objects and advantages will be best understood from a study of the following description taken in connection with the accompanying drawings wherein:

Figure 1 is an elevational view of the extension bit.

Figures 2, 3 and 4 are sectional views taken substantially on the lines 2-2, 3-3 and 4-4, respectively, of Figure 1, and

Figure 5 is an elevational view of a slightly modified form of bit.

Referring more in detail to the drawings it will be seen that the improved extension bit, in the preferred embodiment thereof, comprises a shank 5 equipped as at 6 to facilitate attachment to a drill press, electric drill, or similar tool.

Intermediate its ends the shank 5 is provided with a transverse bore 1 in which is adjustably accommodated a cross-arm 8.

The cross-arm 8 is provided, as shown, with SAE threads cut into the corners thereof for substantially the full length of the cross-arm.

Threadedly engaged with the cross-arm 8 are lock nuts 9 which are adapted to be threaded 35 home on the arm 8 against opposite sides of the bore portion of the shank 5 to secure the crossarm at the desired position of adjustment transversely with respect to the longitudinal axis of the shank.

By providing the threads as above described greater strength is afforded for the lock nuts and the adjustment of the arm 8 is greatly facilitated.

At the end thereof opposite to the end 6 shank 5 is provided with a socket III which receives the squared portion of the drill ll, said squared end of the drill being secured positively within the socket I through the medium of set screws I2.

At one end thereof the cross-arm 8 is diametrically enlarged and split as at |3 to provide an expansible and contractible head embodying complemental jaws l4, IS.

The jaws l4, are provided with complemental notches l6 providing therebetween a noncircular opening to accommodate the noncircular shank portion ll of a bit 2|, or the noncircular shank portion I8 of a slightly modified form of bit shown in Figure 5 and indicated by the reference numeral 20.

For expanding and contracting the clamping head |6, that is to say for drawing the jaws I4, I5 thereof toward and away from one another, there is provided a clamping screw I9 that has threaded engagement with the jaw M as clearly shown in Figure 2.

Also, for positively securing the shank of the bit 2|, or 20, as the case may be, the jaw I4 of the clamping head is provided with a threaded opening 22 to accommodate a set screw 23 that will, of course, bind against the shank of the bit to positively secure the same against axial movement through the opening provided by the notches |6| 5 in the jaws of said clamping head.

From the above it will be apparent that arm 8 may be adjusted transversely relative to the shank 5 for positioning the bit 2|, or 20, as the case may be toward or away from the drill while the said bit 2|, or 20, as the case may be, may have the shank portion thereof secured at the desired adjustment within the opening I5 of the clamping head to secure the bit at the desired position of longitudinal adjustment with respect to the drill Thus the bit 2|, or 20, as the case may be, may be adjusted to control the cutting depth thereof to substantially any degree desired.

It will also be apparent that the structure of the clamping head |6 is such that but slight movement of the jaws l4 and I5 is required to positively .clamp the. shank of the selected bit therebetween. Consequently this expansion or contraction action of the clamping head IE will in no wise tend to weaken said clamping head.

As is well known, in actual practice, as the shank 5 is rotated the drill II and bit 20, or 2|, as the case may be, perform their function the drill boring a central hole thus providing a turning point or bearing for the bit 2|.

It is thought that a clear understanding of the construction, utility and advantages of an extension bit embodying the features of the present invention will be had without a more detailed description.

Having thus described the invention what is claimed as new ls:

An extension bit comprising a shank having a bit receiving socket in its lower end and an enlarged part adjacent said end, said enlarged part having oppositely arranged flat sides and a non- 5 flat side of the enlargement and the other the second flat side 01 the enlargement and means for holding a cutter in one end of the cross arm and at right angles thereto.

EDWARD FREY. 

